Digital Control of Electrical Drives (Power Electronics and Power Systems)

Cover......Page 1
Power Electronics and Power Systems......Page 3
Digital Control of Electrical Drives......Page 4
ISBN 9780387259857......Page 5
Contents......Page 6
Preface......Page 10
1.1 Basic structure of the speed-controlled system......Page 14
Problems......Page 18
2.1 Proportional control action......Page 20
2.1.1 Open-loop and closed-loop transfer functions......Page 21
2.1.2 Load rejection of the proportional speed controller......Page 25
2.1.3 Proportional speed controller with variable reference......Page 26
2.1.4 Proportional speed controller with frictional load......Page 28
2.2 The speed controller with proportional and integral action......Page 29
2.2.1 Transfer functions of the system with a PI controller......Page 30
2.2.2 Load rejection with the PI speed controller......Page 31
2.2.3 Step response with the PI speed controller......Page 32
2.2.4 The PI speed controller with relocated proportional action......Page 39
2.2.5 Parameter setting and the closed-loop bandwidth......Page 41
2.2.6 Variable reference tracking......Page 43
2.3 Suppression of load disturbances and tracking errors......Page 44
2.3.1 The proper controller structure for the given reference profile......Page 45
2.3.2 Internal Model Principle (IMP)......Page 50
2.4 Feedforward compensation......Page 53
Problems......Page 60
3.1 Delays in torque actuation......Page 63
3.1.1 The DC drive power amplifiers......Page 64
3.1.2 Current controllers......Page 68
3.1.3 Torque actuation in voltage-controlled DC drives......Page 70
3.2 The impact of secondary dynamics on speed-controlled DC drives......Page 71
3.3 Double ratios and the absolute value optimum......Page 73
3.4 Double ratios with proportional speed controllers......Page 78
3.5 Tuning of the PI controller according to double ratios......Page 81
3.6 Symmetrical optimum......Page 84
Problems......Page 89
4. Digital Speed Control......Page 91
4.1 Discrete-time implementation of speed controllers......Page 92
4.2 Analysis of the system with a PI discrete-time speed controller......Page 98
4.2.1 The system with an idealized torque actuator and inertial load......Page 99
4.2.2 The z-transform and the pulse transfer function......Page 103
4.2.3 The transfer function of the mechanical subsystem......Page 108
4.2.4 The transfer function of the speed-measuring subsystem......Page 110
4.3 High-frequency disturbances and the sampling process......Page 112
4.4 The closed-loop system pulse transfer function......Page 115
4.5 Closed-loop poles and the effects of closed-loop zeros......Page 120
4.6 Relocation of proportional gain......Page 124
4.7.1 Strictly aperiodic response......Page 125
4.7.2 Formulation of criterion function......Page 129
4.7.3 Calculation of the optimized values for normalized gains......Page 131
4.8 Performance evaluation by means of computer simulation......Page 136
4.9 Response to large disturbances and the wind-up phenomenon......Page 141
4.10 Anti-Wind-Up mechanism......Page 147
4.11 Experimental verification of the discrete-time speed controller......Page 152
Problems......Page 155
5. Digital Position Control......Page 158
5.1 The role and desired performance of single-axis positioners......Page 159
5.2 The pulse transfer function of the control object......Page 162
5.3.1 Derivative action in position controllers......Page 168
5.3.2 Relocation of derivative action into the feedback path......Page 171
5.3.3 The position controller with a minor speed loop......Page 172
5.3.4 Stiffness of the position-controlled system......Page 174
5.4 The discrete-time PD position controller......Page 176
5.5 Optimized parameter setting......Page 185
5.6 Computer simulation of the system with a PD controller......Page 189
5.7 Operation of the PD position controller with large disturbances......Page 192
5.8.1 The speed-limit dependence on the remaining path......Page 195
5.8.2 Enhancing the PD controller......Page 196
5.8.3 The error of the minor-loop speed controller......Page 201
5.9 Computer simulation of the system with a nonlinear PD controller......Page 202
5.10 Experimental evaluation of performances......Page 206
Problems......Page 214
6. The Position Controller with Integral Action......Page 216
6.1 The operation in linear mode and the pulse transfer functions......Page 219
6.2 Parameter setting of PID position controllers......Page 225
6.3 The step response and bandwidth of the PD and PID controller......Page 229
6.4 Computer simulation of the input step and load step response......Page 231
6.5 Large step response with a linear PID position controller......Page 236
6.6 The nonlinear PID position controller......Page 241
6.6.1 The maximum speed in linear operating mode......Page 243
6.6.2 Enhancing the PID controller with nonlinear action......Page 246
6.6.3 Evaluation of the nonlinear PID controller......Page 251
6.7 Experimental verification of the nonlinear PID controller......Page 257
Problems......Page 261
7.1 Tracking of ramp profiles with the PID position controller......Page 264
7.1.1 The steady-state error in tracking the ramp profile......Page 265
7.2 Computer simulation of the ramp-tracking PID controller......Page 268
7.3 Generation of reference profiles......Page 275
7.3.1 Coordinated motion in multiaxis systems......Page 276
7.3.2 Trajectories with trapezoidal speed change......Page 279
7.3.3 Abrupt torque changes and mechanical resonance problems......Page 280
7.3.4 'S' curves......Page 281
7.4 Spline interpolation of coarse reference profiles......Page 284
Problems......Page 290
8. Torsional Oscillations and the Antiresonant Controller......Page 292
8.1 Control object with mechanical resonance......Page 293
8.2 Closed-loop response of the system with torsional resonance......Page 297
8.3 The ratio between the motor and load inertia......Page 302
8.4 Active resonance compensation methods......Page 305
8.5 Passive resonance compensation methods......Page 306
8.6 Series antiresonant compensator with a notch filter......Page 307
8.6.1 The notch filter attenuation and width......Page 308
8.6.2 Effects of the notch filter on the closed-loop poles and zeros......Page 311
8.6.3 Implementation aspects of the notch antiresonant filters......Page 316
8.7 Series antiresonant compensator with the FIR filter......Page 319
8.7.1 IIR and FIR filters......Page 320
8.7.2 FIR antiresonant compensator......Page 321
8.7.3 Implementation aspects of FIR antiresonant compensators......Page 324
8.8 Computer simulation of antiresonant compensators......Page 325
8.9 Experimental evaluation......Page 330
Problems......Page 336
A. C-code for the PD position controller......Page 339
B. ASM-code for the PID position controller......Page 342
C. Time functions and their Laplace and z-transforms......Page 346
D. Properties of the Laplace transform......Page 348
E. Properties of the z-transform......Page 349
F. Relevant variables and their units......Page 350
References......Page 352
C......Page 354
F......Page 355
N......Page 356
S......Page 357
U......Page 358
Z......Page 359